The present invention relates to a device for depositing on a surface automatically, a pasty substance packaged in a fluid-tight and flexible reservoir.
The invention relates also to an automatic marking machine comprising several of these devices.
The device according to the invention is principally intended for the marking of various articles, the pasty substance contained in the fluid-tight and flexible container being in this case constituted by an ink or a paint.
In other applications of the device according to the invention, this pasty substance may be a grease, a glue, a mastic or other caulking or sealing materials, or again a chemical reactant intended to be deposited on an article.
It is known that, in industry, mass-produced articles must often be marked with spots or lines of ink or of paint, to identify the various parts, to mark defective parts or for any other reason.
This marking may be carried out by a marking device comprising a paint refill including an outlet orifice through which the paint is expelled when the refill is compressed.
In Applicant's French Pat. No. 2 298 444 a semiautomatic marking device is described, in which the paint or ink refill is removably fixed, in a fluid-tight housing connected to a compressed air source. The outlet orifice of this refill includes a nozzle whose end carries a cut-off valve which can be opened by simple contact with the surface to be marked.
The expulsion of the paint through this cut-off valve is produced by controlling the introduction of compressed air into the housing to compress the refill, and by placing the end of the nozzle on the surface to be marked to depress and open the valve.
Such a device can be used, for marking automatically, various articles passing, for example continuously, opposite the outlet nozzle of the refill. For this purpose, this marking device may be associated with means enabling it to be brought intermittently into contact with the successive articles to be marked.
Experience has shown that such a device does not give complete satisfaction. In fact, in order that the marking may be carried out under good conditions and to avoid any deterioration of the cut-off valve of the nozzle of the device, the distance between the surface of the articles to be marked and the device must be regulated very accurately. It is not often possible to effect this adjustment with precision, since the parts to be marked may have variable dimensions, an irregular surface or include similar asperities or defects.
It is an object of the present invention to overcome the drawbacks of known devices, by providing an automatic device, notably for marking articles, which is very convenient in use and can be utilized in numerous fields of industry.
According to the invention the device for depositing on a surface automatically, a pasty substance packaged in a fluid-tight and flexible container comprises a fluid-tight housing surrounding this container, the outlet orifice of the pasty substance of this container being connected to an outlet nozzle including at its end a cut-off valve which can be opened by contact with the surface, and the housing being connected to a source of pressurized gas, means being provided to control the admission of this gas into the housing.
According to the invention, this device is characterised in that the housing comprises a cylinder open at its free end and surrounding the outlet nozzle, a piston made fast to this nozzle mounted slidably inside this cylinder, in that means are provided to actuate the sliding of this piston towards the open end of the cylinder, so as to cause the outlet nozzle to project to the outside of the open end of the cylinder, and in that it comprises also means for returning the piston towards the housing after cessation of the action of the compressed gas.
To deposit the pasty substance on articles, passing for example, continuously opposite the device, it suffices to actuate the introduction of pressurized gas into the housing and into the cylinder to cause the compression of the container of pasty substance and the sliding of the piston towards the article.
Due to this feature, the distance between the cut-off valve of the nozzle of the container and the articles does not need to be adjusted with precision.
It suffices in fact for the stroke of the piston to be sufficient to permit the valve to touch the article. In addition, even if the valve of the nozzle touches the article before the end of the possible travel of the piston, there is no risk of deteriorating the valve, due to the damping effect exerted by the compressed gas.
According to an advantageous feature of the invention, the means for actuating the sliding of the piston comprise means enabling the simultaneous introduction of pressurized gas into the housing and into the cylinder.
In this way the compression of the reservoir of pasty substance and the sliding of the piston towards the article are produced simultaneously.
According to a preferred embodiment of the invention, the aforesaid means are constituted by a communicating passage between the cylinder and the housing.
This feature enables notable simplification of the device. Other features and advantages of the invention will also be apparent from the description which follows to be read with reference to the accompanying drawings of preferred embodiments given purely by way of nonlimiting examples.